Seeded silicon nitride powders obtained by carbothermal reduction—nitridation of diatomite and various sources of carbon

Autor: Aleksandra Šaponjić, Svetlana Ilić, Tanja Barudzija, Ana Radosavljević Mihajlović, Maja Kokunešoski, Branko Matović
Rok vydání: 2023
Předmět:
Zdroj: Journal of the Australian Ceramic Society
ISSN: 2510-1579
2510-1560
Popis: In this paper, the effects of the addition of silicon nitride seeds on the phase composition, particle size, and shape of silicon nitride powders obtained by carbothermal reduction-nitridation were studied. Environmentally friendly natural raw material, diatomaceous earth, was used as a Si precursor. Three different carbon sources were used: activated carbon, carbonized sucrose, and carbon cryogel as reducing agents in the molar ratio C/SiO2 = 5. To obtain better-quality Si3N4 powder, the commercial α-Si3N4 powder was added into starting mixtures as seeds in four different quantities. The X-ray diffraction, specific surface area, infrared spectroscopy with Fourier transform, and scanning electron microscopy were employed to characterize the obtained powders. Sucrose as a carbon source enables a major reduction of SiO2 and the onset of β-Si3N4 crystallization at a lower temperature (1350 °C) as well as the complete absence of diatomaceous earth relics. It indicates that the carbothermal reduction-nitridation takes place faster in contrast to the other two carbon sources.
Databáze: OpenAIRE
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